If so I would suggest that they wouldn't risk losing a sale for the sake of supplying a second key.
If you are buying from some oik in a second hand car lot then you run the risk of him turning up t your address and using the spare key he has retained to take the car back......
That's what they used to do.
For what it's worth, I've always refused to purchase a car without the complete original key/fob set, as it means someone else will have them which could give them access to the vehicle.